Recently prevention strategies for breast cancer are focused on lifestyle modification such as diet. Some dietary factors such as Conjugated linoleic acid (CLA) can lower the risk of breast cancer, metastasis and some factors concerning this malignancy. Many studies have been established in this field, but their results are inconsistent. Therefore, we evaluated this association based on systematic review among published scientific literature. We performed an electronic search using PubMed, Cochrane, Scopus, Google Scholar and Persian database (Iran Medex, magiran) to identify relevant studies. We summarized the findings of 8 papers in this review. Although, three cohort studies were not overall identified a protective effect of CLA dietary intake or CLA content in breast tissue on breast cancer incidence, metastasis and death, one of them showed an inverse association after adjusting for age. Also, among case-control studies a weak inverse association between breast cancer risk and CLA dietary intake and serum levels among post-menopausal women was reported. Besides, a clinical trial showed that some indicator of breast tumor decreased after CLA administration among women with breast adenocarcinoma. Lacking published evidence suggested inconsistent results. So, further well-designed studies are required, particularly in considering the main breast cancer risk factors.